3D models to capture and perturb tumour heterogeneity in vitro.

Tumour heterogeneity is a defining feature of cancer and a major obstacle to effective therapy as it drives metastasis, resistance and relapse. Experimental tumour models have largely exploited simplified, homogeneous systems that fail to capture the full biological and spatial diversity of real tumours. Recent advances in 3D models have considerably expanded our capacity to model different dimensions of tumour heterogeneity. These platforms also enable controlled perturbations of cancer-cell-intrinsic and microenvironmental features, including genetic programmes, therapy responses and transport, extracellular matrix composition and mechanics, oxygenation, perfusion, stromal and immune interactions, and tissue architecture. Such perturbations could reveal how different aspects of tumour heterogeneity shape disease progression and therapy response dynamics. However, how close we are to generating 3D models that not only recapitulate the dynamic, multiscale nature of human cancers but also enable systematic perturbations for mechanistic insights remains a key question. In this Review, we summarize the current landscape of 3D models and how effectively they capture tumour heterogeneity, what perturbations they enable, and how these capabilities can be matched to specific biological or therapeutic questions. We also discuss outstanding challenges in model fidelity, standardization, scalability, longitudinal analysis and clinical predictability.